Rein Therapeutics Inc 美股招股说明书（2026-05-04版）

50,000,000 Shares of Common Stock We are selling 50,000,000shares of our common stock at the public offering price of $1.00 per share. Our common stock is listed on the Nasdaq Capital Market under the symbol “RNTX.”On April30, 2026, the last reported sale price of ourcommon stock on the Nasdaq Capital Marketwas $1.355 per share. Investing in our securities involves a high degree of risk. Before making an investment decision, you should carefully review and considerall of the information set forth in this prospectus and the documents incorporated by reference herein, including the risks and uncertainties Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securitiesor determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense. (1)Does not include the reimbursement of certain expenses of the underwriters we have agreed to pay. Please see “Underwriting” beginning on page21 for additional information regarding the total compensation to be received by the underwriters. We have granted the underwriters a 45-day option to purchase up to an additional 7,500,000shares of common stock from us at the public offeringprice, less underwriting discounts and commissions. If the underwriters exercise this option in full, the total underwriting discounts and commissions The underwriters expect to deliver the shares on or about May4, 2026. Konik Capital Partners a division of T.R. Winston& Co TABLE OF CONTENTS Table of Contents ABOUT THIS PROSPECTUS This prospectus, including information incorporated by reference herein, is part of a registration statement that we filed with the U.S. Securitiesand Exchange Commission, or the SEC, under the Securities Act of 1933, as amended, or the Securities Act. This prospectus provides you with a general For investors outside of the United States: Neither we nor the underwriters have done anything that would permit this offering or possession ordistribution of this prospectus in any jurisdiction where action for that purpose is required, other than in the United States. Persons outside of the United The registration statement we filed with the SEC includes exhibits that provide more detail of the matters discussed in this prospectus. Thisprospectus, including information incorporated by reference herein, contains summaries of certain provisions contained in some of the documentsdescribed herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by theactual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits tothe registration statement of which this prospectus is a part. You should read this prospectus and the related exhibits filed with the SEC, together with You should rely only on this prospectus, the information incorporated by reference herein and the registration statement. Neither we nor theunderwriters have authorized anyone else to provide you with different or additional information other than this prospectus or information incorporatedby reference in this prospectus. If anyone provides you with different or inconsistent information, you should not rely on it. Offers to sell, andsolicitations of offers to buy, our common stock are being made only in jurisdictions where offers and sales are permitted. You should assume that the Table of Contents PROSPECTUS SUMMARY This prospectus summary highlights selected information appearing elsewhere in this prospectus and in documents we file with the SEC thatare incorporated by reference in this prospectus. Because it is a summary, it may not contain all of the information that may be important to you. Tounderstand this offering fully, you should read this entire prospectus carefully, including the information incorporated by reference herein, the Overview We are a clinical stage biopharmaceutical company focused on developing novel therapies for the treatment of orphan pulmonary and fibrosisindications with no approved or limited effective treatments. We currently have two product candidates in clinical development, LTI-03 and LTI-01,and multiple candidates in preclinical development focused on fibrosis indications. Our lead product candidate is LTI-03, a peptide for which weconducted a Phase 1b dose-ranging, placebo-controlled safety, tolerability, and pharmacodynamic biomarker activity trial in development for thetreatment of Idiopathic Pulmonary Fibrosis that has demonstrated the ability in both preclinical studies and clinical trials to protect healthy lungepithelial cells and reduce pro-fibrotic signaling. Our second product candidate is LTI-01, a proenzyme that completed a Phase 2a dose-ranging,placebo-controlled trial and a Phase 1b safety, tolerability and proof of mechanism trial in loculated pleural effusion patients, an i